Note: for Ubuntu One Music playlists, a song_id is the nodekey of the file in Ubuntu One. playlist_name is a user-displayable name for a playlist.

Says Chad, """Song IDs should be changed to be independent of some other index. It could be exact file names or a well-defined hash of the contents of a canonical version of the file. I think file_length_in_base10_ascii+SHA224_as_hex of the file conntents is okay. To get something Ubuntu One stores internally, we should add a lookup table in our application_annotations.